Elsmarc - 10:32 pm on Sep 27, 2010 (gmt 0)
Do email verification and it will all go away. I make my living with forum sites and very rarely have a problem with spammers such as you describe.
Or - If it's China and China doesn't matter to you just block the IPs (or range/block of IPs) it is coming from. Personally I don't block China (or anywhere else) because I get a lot of visitors from China on my sites.